Radio-receiver



1953 H. BLOK 2,823,382

RADIO-RECEIVER Filed March 12, 1954 INVENTOR HE NR! BLOK United States Patent RADIO-RECEIVER Henri Blok, Eindhoven, Netherlands, assignor, by mesne assignments, to North American Philips Company, Inc., New York, N. Y., a corporation of Delaware Application March 12, 1954, Serial No. 415,923

Claims priority, application Netherlands March 17, 1953 2 Claims. (Cl. 343-867) The present invention relates to a radio receiver. More particularly, the invention relates to a radio receiver comprising an aerial, more particularly, an incorporated frame aerial structurally united with the apparatus and a highfrequency transformer having a core of ferromagnetic material, more particularly a ferrite of poor conductivity.

If the high-frequency transformer is not provided with magnetic screening, such apparatus is found to have a receiving power which varies to a high extent with the position of the core axis relative to the frame. It may be assumed that this is due to the fact that the highfrequency transformer operates to a considerable degree as a directional aerial and the signal produced thereby increases or attenuates the signal produced by the aerial proper in accordance with the position of the core of ferromagnetic material and with the sense of the connection of the winding of the coils.

In accordance with the invention this phenomenon is utilized to obtain a material increase in receiving power.

In accordance with the present invention, the core of the high-frequency transformer is positioned approxi mately at right angles to the plane of the frame aerial and the sense of the connection of winding of the coils of the transformer is such that the transformer, operating as an aerial, increases the signal produced by the frame aerial.

In general, the component parts of a radio receiver are housed in a rectangular cabinet of wood or other insulating material. In order to obtain a large surface for the frame aerial, it is usually arranged in a diagonal plane at right angles to the top and bottom surfaces of the cabinet. Provision is often made of two frame aerials each in a ditfcrent diagonal plane, used separately or in con unction.

The axis of the coils contained in the receiver system is not vertical in this case, as is common practice to do, but horizontal, approximately at right angles to the front surface of the cabinet.

In order that the invention may be readily carried into effect, it will now be described with reference to the accompanying drawing, wherein:

Fig. l is a perspective schematic of an embodiment of a radio receiver viewed from the rear;

Fig. 2 is a lateral view of the high-frequency transformer of the embodiment of Fig. l; and

Fig. 3 is a schematic diagram of the circuit arrangement of the high-frequency transformer of the embodiment of Fig. 1.

Referring to Fig. 1, reference numeral 1 designates the cabinet, which is opened at the rear. The cabinet comprises the frame aerials 2 and 3, each of which may comprise one or more turns and which may be included separately or in conjunction in the input circuit of the receiver. The cabinet comprises furthermore a chassis 4, in which and on which the various parts of the apparatus, for example. the tubes 5, are mounted.

' It is assumed that provision is made of a high-frequency "ice transformer comprising a cylindrical core 6 of ferromagnetic material of poor conductivity, for example, a ferrite, and two coils 7 and 8. The length of the core which may be bored, is large with respect to the diameter. The transformer may be connected as is indicated in Fig. 3 so that, by switching from one frame aerial to the other, the directivity of the aerial system may be changed and stations in different directions from the receiver may be received under conditions of maximum aerial sensitivity without changing the physical position of the receiver. The apparatus may, for example, be adapted to receive the medium-wave range extending from 200 to 600 meters.

The primary coil 7, surrounding the secondary coil 8, will in this case comprise in general only a few turns. The secondary coil 8 is included in the input circuit of a high-frequency amplifier or of a mixing tube of the receiver system.

The transformer is mounted on a plate 9, which is secured to the chassis 4 proper in a manner such that the axis of the core 6 is approximately at right angles to the front surface of the apparatus. Since the angle between the frames 2 and 3 is assumed to be obtuse, the angle between the plane of the front surface of the receiver and the planes of the frame aerials is comparatively small, so that the axis of the core 6 is substantially at right angles to the planes of both of the frame aerials. By connecting the supply wires for the coils so that the signal picxed up by the coils is in the same sense as the signal picked up by the frame aerials, the antenna effect of the transformer, operating as a directional aerial, contributes to the antenna effect of the frame aerials.

The transformer is not screened magnetically by means of a completely closed sleeve.

If more wave ranges should be received, a high-frequency transformer is used for each of these ranges, all cores being arrangeable at right angles to the front surface of the apparatus.

While the invention has been described by means of a specific example and in a specific embodiment, I do not wish to be limited thereto, for obvious modifications will occur to those sKilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A radio receiver comprising a radio signal receiving assembly, a frame aerial system serving as an antenna for intercepting a radiated signal and comprising a signal PICK-11p winding arranged in a given plane and in close proximity to said assembly, said assembly comprising a high frequency transformer comprising a signal processing coil having a core of magnetic material and a longitudinal axis tnerethrough, said coil being arranged on said assembly with its said axis substantially perpendicular to the said given plane and being positioned to intercept said radiated signal, said coil being coupled to said signal pick-up winning in the same sense thereby producmg addition of the signals of said pick-up winding and said coil.

2. A radio receiver as claimed in claim 1, wherein said frame aerial system comprises two signal pick-up loops arranged in planes forming an obtuse angle therebetween, and further comprising a switching member for selectively coupling said loops to said signal processing coil.

References Cited in the file of this patent UNITED STATES PATENTS 2,074,944 Sjostrand Mar. 23, 1937 2,383,415 Polydoroif Aug. 21, 1945 FOREIGN PATENTS 355,858 Great Britain Sept. 3, 1931 

